fix a memory leak for getline()
fix a memory leak for getline()

The memory allocated by getline() is not freed.
This may cause some tool like clang memory
leak sanitizer complain.

Signed-off-by: Yonghong Song <e76892bbe783db2f627de1232e139db4de43da60@fb.com>

tuxology/bcc,tuxology/bcc,brendangregg/bcc,iovisor/bcc,iovisor/bcc,brendangregg/bcc,iovisor/bcc,iovisor/bcc,mcaleavya/bcc,tuxology/bcc,tuxology/bcc,brendangregg/bcc,tuxology/bcc,mcaleavya/bcc,mcaleavya/bcc,brendangregg/bcc,mcaleavya/bcc,brendangregg/bcc,iovisor/bcc,mcaleavya/bcc